Implement the -Wimplicit-rhs-quantification warning (#23510)
Fixed #23510 (closed)
Added new -Wcompat
warning -Wimplicit-rhs-quantification
In accordance with GHC Proposal #425, GHC will stop implicitly quantifying over type variables that occur free on the right-hand side of a type synonym but are not mentioned on the left-hand side. Type synonym declarations that rely on this form of quantification should be rewritten with invisible binders.
For example:
type T1 = 'Nothing :: Maybe a -- old
type T1 @a = 'Nothing :: Maybe a -- new
This warning detects code that will be affected by this breaking change.